The invention relates generally to medical devices and procedures. More particularly, the invention relates to apparatus and methods for minimally invasive instrumentation and implants for spinal fusion.
Bone fixation devices, such as, for example, bone screws, interbody implants, staples, pins, wires and/or clamping mechanisms, can be used in various medical procedures. For example, known bone screws can be used to repair fractured bone tissue by securing adjacent portions of the bone tissue together to stabilize and/or limit the movement of bone tissue. Known interbody implants can be used between adjacent portions of bone tissue to provide support for and to facilitate bone growth between the portions of bone tissue. For example, some known bone screws and interbody implants can be used as a part of a spinal fixation procedure.
In some procedures, for example, a facet screw can be inserted across the facet joint of the spinal column to fix and/or limit the motion of the facet joint. Such known procedures can include, for example, translaminar facet screw fixation, which includes inserting a facet screw from the base of the spinous process on the contralateral side and through the lamina to traverse the facet joint in a plane perpendicular to the joint surfaces. Facet screws can also be inserted using a transfacet approach, which involves inserting a bone screw via a midline incision or an ipsilateral incision. Other procedures involve positioning an implant in the facet joint. Such known procedures, however, often involve the use of multiple tools and/or multiple steps, and are performed in an open incision in which the facet joint is exposed and tissue retracted sufficiently to allow placement of the screw through the facet, or placement of the interbody implant between the portions of the facet, under direct vision. Since placement of the facet screw and the implant are accomplished from two different approaches to the facet, procedures that employ facet screw fixation and implant placement into the facet joint involve retraction of sufficient tissue around the facet to open the incision to simultaneously expose both approaches for use by the surgeon.
Thus, a need exists for improved insertion tools, implants, and procedures for insertion and securement of implants at locations within a patient's body that can minimize intrusion into tissue along the approach to and around the implantation location.